Counties in Minnesota by share of days unhealthy for sensitive groups or worse (US EPA AQI)

Beltrami County had the highest share of days unhealthy for sensitive groups or worse (US EPA AQI) of 22 counties in 2024, at 1.1%. Winona County had the lowest, at 0%. The median was 0.3%. Source: EPA.

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Highest1.1Beltrami County
Median0.322 counties

Map of counties, 2024

Anoka County: 0.3 %Becker County: 0.5 %Beltrami County: 1.1 %Blue Earth County: 0 %Carlton County: 0.3 %Cass County: 0.3 %Cook County: 0.8 %Crow Wing County: 0.3 %Dakota County: 0.3 %Goodhue County: 0 %Hennepin County: 1.1 %Lake County: 0.3 %Lyon County: 0.5 %Mille Lacs County: 0 %Olmsted County: 0.3 %Ramsey County: 0.3 %St. Louis County: 0.8 %Scott County: 0.3 %Stearns County: 0 %Washington County: 0 %Winona County: 0 %Wright County: 0.8 %
  • Under 0.3
  • 0.3 to 0.7
  • 0.7 and over
  • No data
%, 2024. Hatched areas have no value for this period. Source: Invokely calculation with data from EPA. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2024

Beltrami County: 1.1 %Beltrami County1.1Hennepin County: 1.1 %Hennepin County1.1Cook County: 0.8 %Cook County0.8St. Louis County: 0.8 %St. Louis County0.8Wright County: 0.8 %Wright County0.8Becker County: 0.5 %Becker County0.5Lyon County: 0.5 %Lyon County0.5Anoka County: 0.3 %Anoka County0.3Carlton County: 0.3 %Carlton County0.3Cass County: 0.3 %Cass County0.3Crow Wing County: 0.3 %Crow Wing County0.3Dakota County: 0.3 %Dakota County0.3Lake County: 0.3 %Lake County0.3Olmsted County: 0.3 %Olmsted County0.3Ramsey County: 0.3 %Ramsey County0.3Scott County: 0.3 %Scott County0.3Blue Earth County: 0 %Blue Earth County0Goodhue County: 0 %Goodhue County0Mille Lacs County: 0 %Mille Lacs County0Stearns County: 0 %Stearns County0Washington County: 0 %Washington County0Winona County: 0 %Winona County0Beltrami County: 1.1 %Beltrami County1.1Hennepin County: 1.1 %Hennepin County1.1Cook County: 0.8 %Cook County0.8St. Louis County: 0.8 %St. Louis County0.8Wright County: 0.8 %Wright County0.8Becker County: 0.5 %Becker County0.5Lyon County: 0.5 %Lyon County0.5Anoka County: 0.3 %Anoka County0.3Carlton County: 0.3 %Carlton County0.3Cass County: 0.3 %Cass County0.3Crow Wing County: 0.3 %Crow Wing County0.3Dakota County: 0.3 %Dakota County0.3Lake County: 0.3 %Lake County0.3Olmsted County: 0.3 %Olmsted County0.3Ramsey County: 0.3 %Ramsey County0.3Scott County: 0.3 %Scott County0.3Blue Earth County: 0 %Blue Earth County0Goodhue County: 0 %Goodhue County0Mille Lacs County: 0 %Mille Lacs County0Stearns County: 0 %Stearns County0Washington County: 0 %Washington County0Winona County: 0 %Winona County0
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2024 (%)Change on 2023
1Beltrami County1.1-0.6 pts
1Hennepin County1.1-3.6 pts
3Cook County0.8+0.5 pts
3St. Louis County0.8-1.4 pts
3Wright County0.8-5.2 pts
6Becker County0.5-1.7 pts
6Lyon County0.5-3.1 pts
8Anoka County0.3-4.4 pts
8Carlton County0.3-1.1 pts
8Cass County0.3-1.1 pts
8Crow Wing County0.3-2.2 pts
8Dakota County0.3-2.4 pts
8Lake County0.3-0.2 pts
8Olmsted County0.3-3.8 pts
8Ramsey County0.3-2.4 pts
8Scott County0.3-4.4 pts
17Blue Earth County0n/a
17Goodhue County0-2.1 pts
17Mille Lacs County0-2.1 pts
17Stearns County0-3.8 pts
17Washington County0-3.3 pts
17Winona County0-1.7 pts

Other periods

About this ranking

Days with a daily Air Quality Index above 100 (unhealthy for sensitive groups, unhealthy, very unhealthy or hazardous) as a percentage of the days of the year with an AQI in a US county. Calculated by Invokely from the day counts in the EPA AirData annual summaries; the counts are stored with each value.

Use the share rather than the number of days to compare counties, since the days with an AQI differ. United States counties with air quality monitors only, about 1,000 of some 3,100 in recent years; a county without monitors has no value. The number of days with an AQI differs between counties because some monitors run only in the ozone season.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. 18 counties with data in other periods have no value for 2024 and are left out rather than filled from another source. Equal values share a rank.

How to cite

U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Environmental Protection Agency. (2026). EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts (Counties in Minnesota by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2024) [Data set]. Retrieved October 12, 2026, from https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual

MLA 9

EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts, Counties in Minnesota by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2024. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/unhealthy-air-quality-days-share/minnesota-counties?period=2024. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts. Counties in Minnesota by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2024. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/unhealthy-air-quality-days-share/minnesota-counties?period=2024.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts, Counties in Minnesota by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2024 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/unhealthy-air-quality-days-share/minnesota-counties?period=2024 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_minnesota_by_2024,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts: Counties in Minnesota by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2024}},
  year = {2026},
  howpublished = {Data set},
  url = {https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/unhealthy-air-quality-days-share/minnesota-counties?period=2024. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download\_files.html\#Annual. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Environmental Protection Agency
TI  - EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts: Counties in Minnesota by share of days unhealthy for sensitive groups or worse (US EPA AQI), 2024
PY  - 2026
DA  - 2026/07/13
PB  - U.S. Environmental Protection Agency
DB  - Invokely
UR  - https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual
L2  - https://invokely.ai/rankings/unhealthy-air-quality-days-share/minnesota-counties?period=2024
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/unhealthy-air-quality-days-share/minnesota-counties?period=2024.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  - 
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Questions

Which county has the highest share of days unhealthy for sensitive groups or worse (US EPA AQI)?

Beltrami County, with 1.1% in 2024, according to EPA.

Which county has the lowest share of days unhealthy for sensitive groups or worse (US EPA AQI)?

Winona County, with 0% in 2024.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: days with an AQI above 100 as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 18 counties have no value for 2024 and are not ranked.

Share of days unhealthy for sensitive groups or worse (US EPA AQI): other rankings

Counties in Minnesota: more rankings